2,3,4,5‐Tetramethyl‐1‐natriopyrrol — ein Azacyclopentadienyl‐Ligand in neuartiger Brückenfunktion

Abstract

N-Atomen betragen fast genau 90". Die beobachtete Geometrie laDt sich somit als Ergebnis von Co-Co-AbstoDung und Riickstellkraft infolge der Winkeldeformation an den p-N-Atomen verstehen.Die Kristallstruktur von 2 kann iiber die Ahnlichkeit der Kationenteilstruktur mit einer hexagonal dichtesten Pakkung (hcp) beschrieben werden: In den hexagonal gepackten Schichten von Kationen gemaD der Stapelfolge AB,AB, . .(h) sind alle Liicken von Bre-Ionen besetzt"].

Structure Determination of Unsolvated Potassium, Rubidium, and Cesium Carbazolates

“…Trimeric, tetrameric, and hexameric structures were found . Furthermore, the crystal structure of unsolvated sodium tetramethylpyrrolate is known, which forms a polymeric ladder structure with bridging σ- and π-bonded pyrrolate anions …”

“…9 Furthermore, the crystal structure of unsolvated sodium tetramethylpyrrolate is known, which forms a polymeric ladder structure with bridging σ-and π-bonded pyrrolate anions. 10 Solid-state structures of solvated alkali-metal carbazolates have been determined by us and others. Dimeric and monomeric complexes are found, along with compounds with uncoordinated carbazolate anions.…”

New Alkali Metal Primary Amide Ladder Structures Derived fromtBuNH2: Building Cisoid and Transoid Ring Conformations into Ladder Frameworks

“…Edge bonds come in three distinct pairs: adjacent long ones (Na1 ± N3, Na1 ± N4; mean length 2.494 ), adjacent short ones (Na2 ± N1, Na3 ± N1; mean length 2.372 ) that lie directly opposite the first pair, and intermediate ones (Na2 ± N4, Na3 ± N3; mean length 2.433 ) that face each other across the ladder. Without the complication of solvent molecules, the bond length pattern is much simpler in the only other crystallographically characterised sodium amide polymeric ladder 5: [9] one rung type of intermediate length with alternating short and long edge bonds (respective lengths: 2.411, 2.351 and 2.694 ). The longest N ± Na bonds in 7 [2.566(5) ] are the dative ones involving the amine molecules.…”

“…[4] An important point that appears not to have been addressed previously in this developing theme is considered here: the precursor dimeric rings from which the ladders are constructed can, in theory, start off with either a cisoid or transoid arrangement of amido substituents provided that R 1 =R 2 . Hitherto, most crystallographically characterised ladder complexes have failed to meet this condition on account of having equivalent R groups [e.g., as in the dibenzylamide 1 [5] and the bis(trimethylsilyl)phosphide 2 [6] ] or R groups tied together as part of a heterocyclic ring (e.g., as in the hexamethyleneimide 3, [7] the piperidide 4, [8] the pyrrolide 5, [9] and the pyrrolidide 6 [3] paper describes the novel sodium amide´amine polymeric ladder complex 7, which features both conformations simultaneously in its wavelike structure. Also reported is the heterobimetallic derivative 8, another curved ladder species, but a finite oligomer with a different combination of cisoid/ transoid units to that found in 7.…”